The ASA upheld the complaints, including from the National Association of Catholic Families and the Catholic Truth Society, saying that the headline was "likely to cause
serious or widespread offence".

It said the phrase "immaculate contraception" was likely to be seen as a pun on the Roman Catholic dogma of the Immaculate Conception.

Part of the advert, which appeared on the London Underground, read: "Immaculate contraception ? If only.

"It might be Christmas time, but condoms still split and pills still get forgotten."

Schering Health Care said the headline was intended as a pun to indicate that no contraception method was perfect or foolproof, and that Levonelle was available in the event planned contraceptive methods failed.

It immediately removed the posters from the London Underground, cancelled press bookings and promised not to use the advert again.

The ASA rejected a second area of complaint that the poster was irresponsible because it could "encourage casual sex and trivialised unwanted pregnancy".